About MS
MS Introduction
We all know how important it is to have access to the right tools to overcome obstacles. MS Village provides the superior resources and right information to help you or someone you may care about on the journey through MS.
What is MS?
Multiple sclerosis (MS) is a chronic, debilitating disease that attacks the myelin in the central nervous system—the protective sheath that covers the nerve fibers in the brain and spinal cord (central nervous system, or CNS). When attacked, the transmission of nerve impulses are either slowed or blocked, affecting certain cognitive and physical abilities and skills.
How nerve cells work
In MS, a type of immune cell known as a T cell becomes activated and starts to multiply; how it becomes activated, is still unclear. However, these immune cells cross the blood-brain barrier into the CNS. The blood-brain barrier is a layer of cells that surrounds and protects the CNS from large molecules, immune cells, and potentially damaging substances passing from the bloodstream into the CNS.
Once inside the CNS, these immune cells attack the myelin causing inflammation and axon damage, leaving scar tissue called lesions or plaques.
Due to the damage and presence of plaques, information cannot pass along the nerve cells in the CNS—resulting in common neurologic, sometimes nonspecific, symptoms. These symptoms can range in severity, from numbness in the limbs and stifled speech to paralysis and loss of vision. It’s a challenging and unpredictable disease, but new treatments and advances in research are giving people new hope for a cure.
Although the causes of MS are still unknown, extensive research and studies have provided progressive insight into the origins and triggers. Scientists believe MS is most likely caused by a combination of immunological, environmental, infectious and genetic factors.
Immunologic
MS is widely believed to be an autoimmune disease. Scientists hypothesize that the immune system has an irregular response to the myelin (the protective sheath surrounding the nerve fibers) in the central nervous system; but why the immune system reacts adversely remains unknown. However, in ongoing studies, researchers have been able to identify which immune cells are attacking and some of the causes, and why they seem to be attracted to myelin and its destruction.
Environmental
Researchers are linking many environmental factors, including variations of geography, demographics, and migration patterns to the cause of MS.
MS is more common in people who live farther from the equator. Areas with less sunlight exposure (vitamin D intake) suggest the population is at higher risk of developing MS. Vitamin D is believed to have an advantageous effect on the immune function which helps protects against autoimmune diseases like MS.
Other studies show MS can occur in people over a specific time period and/or specific area. This is commonly identified as an MS Cluster. These clusters are being closely examined (people exposed to environmental and industrial toxins, diet, or high levels of trace metals) in hopes they will provide definitive evidence that environmental factors are the cause of MS.
In addition, studies of migration patterns have shown that people born in an area of high risk MS, who move to an area of lower risk before the age of 15, gain the resistance of their new environment. Such data implies exposure to a certain environmental agent before puberty may act as protection against MS later on.
Infectious
Research confirms exposure to viruses, bacteria and other harmful microbes during childhood causes demyelination and inflammation. Such evidence makes it possible that an infectious agent can be the cause of MS. Scientists are studying several viruses and bacteria, including Chlamydia pneumonia, human herpes virus-6, measles, canine distemper and Epstein-Barr to gain more conclusive and well-rounded knowledge about the infectious-MS relationship.
Genetic
MS is not considered a hereditary disease; though, several genetic variations have shown to increase the risk of developing the disease. Having a first-relative such as a parent or sibling increases the risk of developing the disease in comparison to the general population. Scientists theorize MS develops because a person is born with a genetic predisposition that reacts to some environmental agent that triggers an abnormal autoimmune response.
No matter who you are, or where you live, anyone can develop MS. It is estimated that 2.5 million (1) people worldwide and 55,000 to 75,000 people in Canada (2) have MS. It is also projected that, in Canada, 1,000 new cases are diagnosed each year (3). MS typically develops during the family and career building years, between the ages of 15 and 40 (4), and with an average age of onset of between 31 and 33 years (5). As well, MS occurs more frequently in women than in men—supporting the autoimmune disease theory as more women than men develop autoimmune conditions.
Types of MS
MS is generally segmented into four distinct courses. Each course has its own set of characteristics and degrees of severity.
Relapse-Remitting MS (RRMS)
People with this type of MS experience distinct attacks (also called relapses or exacerbations) that are either partially or fully recovered from. Between attacks there is generally no visible progression of the disease. Approximately 75% of people are initially diagnosed with relapse-remitting MS.
Primary-Progressive MS (PPMS)
People with this type of MS experience a steady disease progression from onset, with no definitive remission periods. This is a less common type of MS that usually appears in people in their forties and is the only course that affects men and woman equally (1).
Secondary-Progressive (SPMS)
People with this type of MS experience a direct progression from the initial relapse and remitting course. This type of MS steadily progresses with or without relapses. Attacks range from mild to severe and usually without full recovery.
Progressive-Relapsing MS (PRMS)
People with this type of MS experience a steady progression from onset, with acute attacks along the way. Following these relapses, people may or may not experience some form of recovery.
References:
1. What is MS? National MS Society. Available at: http://www.nationalmssociety.org/about-multiple-sclerosis/what-is-ms/index.aspx.
2. What causes of MS? National MS Society. Available at: http://www.nationalmssociety.org/about-multiple-sclerosis/what-causes-ms/index.aspx.
3. Who gets MS? National MS Society. Available at: http://www.nationalmssociety.org/about-multiple-sclerosis/who-gets-ms/index.aspx.
4. Frequently asked questions. Multiple Sclerosis Society of Canada. Available at: http://mssociety.ca/en/information/faq.htm.
5. Who gets MS. MS-Network. Available at: http://www.ms-network.com/intl/msnetwork/general/guide_understanding_ms/what_is_ms/who_gets_ms/who_gets_ms.jsp.
Additional sources:
What causes MS? National Multiple Sclerosis Society. Available at: http://www.nationalmssociety.org/about-multiple-sclerosis/what-causes-ms/index.aspx.
What is MS? National MS Society. Available at: http://www.nationalmssociety.org/about-multiple-sclerosis/what-is-ms/index.aspx.
Types of MS. Multiple Sclerosis Society of Canada. Available at: http://mssociety.ca/en/information/types.htm.